It is known that with the increasing popularization of the use of mobile phones, not only has the number of users of the cellular telephone service increased, but there has also been a demand that grows day by day demanding an increasingly better signal quality, and a greater traffic of digital data. All of the above is only appreciated by the user if it is available in a consistent way in the most varied geographies and environments, that is to say, with great geographic coverage.
To respond to these market demands, for years there has been a growing activity of installing antennas for cellular telephony in the public space, but, in contrast, the same users who demand more and more telephone services do not hide their annoyance against the invasive and unpleasant aspect of the antennas. It is that lack of visual integration of the antennas for cellular telephony, either in the urban or in the rural environment, that is due to the fact that for a purely technical necessity these antennas must be mounted at great heights and in open spaces very visible with the technical objective of obtaining adequate signal coverage. For this reason, the antennas for cellular telephony are exposed in a gross way, mainly because the visual appearance of such antennas for cellular telephony responds purely to technical and non-aesthetic issues. For these reasons, the antennas themselves, as well as their support structures, their cables, and auxiliary installations, form an aesthetic complex that is invasive and visually objectionable to their surroundings.
In response to this growing proliferation of “invasive” antennas for cellular telephony and with the aim of minimizing their visual impact on the environment, bearing in mind that at present this type of antenna has not yet obtained a good integration with the environment and without hampering its technical performance. In the prior art, a variety of alternative designs have been proposed to avoid the exposure of the antennas. This variety of designs is recurrently based on applying a technique of mimicking the environment.
At present, this mimicry with the environment has been obtained, for example, by disguising the antennas under various forms present in nature, in this way the telephone companies have considered that it would be possible to obtain an ingenious mimicry with the surroundings using facilities that simulate diverse elements of the reigning vegetation, such as false trees, false palms, false cactus, etc. An example of this type of camouflage can be observed in the U.S. Pat. No. 5,787,649A—the proposal of an antenna structure that simulates a palm tree. In practice, cell phone antennas are painted the same color as the false palm leaves and intertwine in a way to confuse the observer visually. These camouflages do not shield the electromagnetic signal since they do not enclose or cover the antenna, they only disguise it, but it is still in sight. It is noteworthy that by the mere fact of simulating nature, they enjoy the benefits of natural adaptation to resist atmospheric factors, such as the structural loads of wind and rain, being able to place them in locations and orientations that favor their protection. The more hidden and less visible the better, contrary to what happens with the advertising billboards objective of the present invention, which should be exposed as visibly and as clear as possible.
Other techniques of mimicking or hiding antennas for cellular telephony are based on the imitation of building parts such as false chimneys, or the incorporation of false water tanks, false corners, or simulating certain building extensions among other tricks of mimicry, that is, always adding a new component that would not originally be there except for the need to incorporate new antennas. These structures totally or partially cover the antennas, modify the original environment, and are conditioned on their size, position and number of antennas or equipment to contain or hide. The fake water tanks limit the space where the antennas contain their external cylindrical shape, and once installed do not allow modifications to expand their capacity and ultimately continue to introduce more invasive elements that do not integrate with the environment. Incorporation into simulated chimneys or building continuations is very limited in size, amount of antennas, permeability and reach obtained because they are conditioned to be integrated into the roofs of buildings with structural constraints and face a growing urban regulation against visual pollution.
A person not skilled in the art might think that if one takes into account that cell phone antennas need generous air space for their installation and need to be arranged at great heights, they could easily be mounted on large size advertising billboards of the type which is used outdoors, such as along motorways, avenues and roads, which could be an appropriate solution. However in practice, to date, the billboard manufacturers have not found a suitable way to integrate the billboard with the antennas, and for this reason the billboards of the type used for the present invention do not integrate or hide antennas therein. This is understandable, since the manufacturers of billboards using the known techniques to date have been conditioned to use traditional metallic materials for the frame, as well as the rolls of cover plates, which shields the electromagnetic waves, preventing them from integrating antennas in their designs.
By way of example, patent application WO2011104393, entitled “Single-column advertising structure including a mobile telephone station”, highlights the difficulty of manufacturers of public signage to integrate the antennas into the billboards. As illustrated and described in the patent application, the antenna must necessarily protrude above the first and second metal platforms and above the metal frame where the printed faces of the billboard are mounted, so that the antenna is exposed. If the antenna does not protrude above the billboard, the very structure of metal profiles and plates that are absolutely necessary to support structurally and cover laterally the billboard itself, would shield electromagnetic waves. A simple and clear representation of this type of signage merely serves to support the antennas above the billboard itself without hiding them is illustrated in FIG. 1, herein attached, being that FIG. 1 is representative of the prior art.
In FIG. 1 of the prior art, a typical external distribution of various types of antennas, including high gain cell phone antennas, can be clearly seen, where it is impossible to camouflage the mentioned antenna due to the screening effect that would result from the billboard's own metal structure. The FIG. 1, representative of the closest known prior art related to large size signage of the type of interest for the present invention has been illustrated, so as to discover the various layers of coverage to the reader, up and to the right, the various layers that make up the visible side of advertisement, in the foreground the outer layer, either a canvas or layer of paint containing the advertising design; below it is a layer of metallic coating obtained with metal sheets upholstering the metal grid that is last in the interior of the billboard as a grid or main frame and that provides the necessary structural resistance to the whole.
Those skilled in the art are well aware that large advertising billboards must be constructed in such a way that not only are they self-supporting, that is, not only must they be strong enough to support their own weight, but must also be strong enough to withstand the conditions of meteorological rigor to which they will be subjected, mainly loads by winds and rains, as well as the snow and other factors depending on the local climatology. In particular, billboards are especially vulnerable to wind and rain loads, due to large exposed surfaces (such as ship's sails), resulting in excessive accumulation of loads by wind and rain pressure.
Although the manufacturer knows in advance the conditions of wind and rain load that will act on his billboard in a certain place of installation, he is also fully aware that the advertising faces must be installed in a commercially useful way, that is, prioritizing the orientation of the faces advertising to be visible to the people who travel with their vehicles or simply as pedestrians. Therefore, manufacturers know that the position in which the advertising faces are facing the direction of the wind or rain is not always the most favorable, and for this reason, the billboards are constructed prioritizing their mechanical resistance according to the rules, resorting to the use of metallic profiles, screwed or welded in connection knots to after forming the main frame to cover them with the corresponding metallic panels in order to obtain the necessary mechanical resistance of the frame and the support surface for the advertising canvases.
For that reason, if a telephone company tried to use the current large advertising billboards available in the market of frame and metal coating and tried to camouflage inside the billboard the antennas for cellular telephony, it could not obtain electromagnetic signal of service, since the own structure of the billboard would almost completely shield the emission and reception of electromagnetic waves. In view of such circumstances, the inventors here understand that there is still a need to provide a new type of structure of a large advertising billboard that allows the complete concealment of the antennas for cellular telephony and yet allows a complete and reliable permeability to the electromagnetic waves of the mentioned antennas for cellular telephony with a complete and easy access for their maintenance and updating, all without damaging the mechanical structural response to wind, rain and similar loads.